I help organise a weekly Twitter chat about Local Government Social Media @lgovsm which uses the hashtag #lgovsm. It starts Tuesday at 8:30pm Western European Time and continues for an hour or 2. Afterwards, I normally use searchhash.com to collect all tweets, as follows:-
Type the #hashtag in "Enter hashtag to search for"
Enter dates to search for using format YYYY-MM-DD
Click on Search tweets and wait for results to load
Click on Download these results in CSV format (opens in Excel, OpenOffice etc)
The results can now be saved in Google Docs, shared and a link tweeted in #lgovsm
Following steps 1 to 3, I search for tweets from Tuesday 7th April 2012: -
Completing step 4 gives me these results: -